Thursday, December 21, 2023

Re: Weird network performance with iwn(4)

On Wed, Dec 20, 2023 at 07:54:47PM +0000, Lévai, Dániel wrote:
> Danel Levai wrote:
> > Stuart Henderson wrote:
> > > I checked for openwrt support but your AP has a relatively uncommon
> > > Realtek SoC and it seems fairly unlikely to happen so you're probably
> > > stuck with the vendor firmware.
> > >
> > > Maybe try forcing "mode 11n" or "mode 11g" with ifconfig and see if
> > > that's any better.
> >
> > Interestingly enough, "mode 11g" won't join the AP. 11n works and it's a steady
> > 300KByte/sec, it doesn't go up and down like with 11ac.
> >
> > Anyway, I'll see if I can find myself another AP to deploy here, maybe it's just some
> > fringe compatibility issue.
> >
> > Daniel
>
> Just for the record, I totally missed trying the 2.4GHz SSID of this AP (it has a different name). I was only trying 5GHz with all modes - no wonder .11g wouldn't join (brain freeze)...
> So .11n actually works on 2.4GHz with this AP and iwm(4), and has a download speed of around 1,5-2,0MByte.
>
> Daniel
>
>

This means the performance issue is specific to 11ac mode, correct?

If so, could you send me a pcap of 5GHz beacons from this AP?

To capture beacons, associate to the AP again (the easy way to ensure we
don't capture unrelated things):

ifconfig iwm0 join apname chan 44 wpakey ...

Once 'status:' shown by ifconfig iwm0 is "actve", run this for about one second,
then terminate with Ctrl-C:

tcpdump -n -i iwm0 -s 1500 -w /tmp/iwm.pcap -y IEEE802_11_RADIO type mgt subtype beacon

To verify whether the file contains the expected beacons, run:

tcpdump -r /tmp/iwm.pcap | grep beacon

You should see at least one line such as:

09:18:15.918261 802.11: beacon, ssid (apname), rates, ds, tim, country, rsn, 70:5, 59:2, htcaps, htop, 127:8, vhtcaps, vhtop

Now send me the iwm.pcap file offlist. Thanks!

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